The ability to detect toxic and flammable gasses is important for the safe operation of numerous, highly complex industrial enterprises. Both fixed and portable detectors are currently used to detect toxic and flammable gases released from industrial processes. In order to reduce detection interruptions, low-power gas sensors have been used to increase portable detector battery life,
Various systems are known for the detection of flammable gasses. Some of the flammable gas detection systems include Micro-Electro-Mechanical Systems (MEMS) technologies, however the reliability and long-term stability of these MEMS gas detectors has not yet reached the commercial stage. Various flammable gas detection systems have included commercial platinum wire resistance-based pellistor flammable gas sensors, however portable detector battery life can be shortened by the power consumption in such sensors. Such a commercial pellistor consists of a platinum-coiled wire covered by bead-like catalyst, which is generally made of metal oxides on which noble metals are deposited. In other cases, a noble metal is incorporated in the body of the bead. The platinum wire may function as a heater for the bead, as well as a temperature sensor.
Detection of flammable gases (e.g., methane (CH4), propane (C3H8), butane (C4H10), hydrogen (H2), and carbon monoxide (CO)) is of high importance for safety and process control in coal and petrochemical industries, as well as for safety of homes and buildings, where flammable gases are burned for heating and cooking Some flammable gas sensors include a thick film of SnO2 deposited on ceramic substrate, where the ceramic substrate is heated by a platinum heater. Such a ceramic sensor is seldom employed in portable applications, as it may consume about 850 mW for heating the substrate to the optimum sensing temperature and reading the detector response. A high level of power consumption in any portable application requires frequent battery replacement, which may raise both productivity and safety issues in field operation, These sensors also include limited flammable gas sensitivity, sometimes detecting flammable gases only at relatively high concentrations, including above 500 ppm. In safety applications, it may be useful to detect lower gas concentrations and provide an early alarm against a potentially or currently hazardous situation.